Cmax heated front and rear windscreen probelms?

I have an 08 Cmax TDI where the front windscreen only de-mists the passenger side and the rear screen only de-mists half way down. I tried the obvious thing of replacing the fuses, sadly this hasn't worked. I'm not in favour of smashing both windows and claiming on the insurance, so I hoping someone out there has had the same problem and found a simple cure! Any thoughts greatly appreciated
Percy